The present invention relates to a billing method in a telecommunications system. The invention relates more specifically, but not exclusively, to a billing method which can be carried out with an identification card as well as to a corresponding identification card.
In telecommunications networks, for example in telecommunications networks based on the Global System for Mobile Communications (GSM) standard, the connection fees to be charged depend upon various parameters, among others the duration of the connection, the time of day and the geographic location of the calling and called user. These parameters, in particular the duration of the connection, are established in the infrastructure of the network, for example in a billing center. From these parameters the connection fee can then be determined and can be charged to the account of the user at the network operator or at a financial institution. This billing method is extremely time-consuming and expensive for the network operator, and requires a complex billing system and many manual or semi-automatic operations.
In addition to these post-paid billing methods, prepaid systems are also known. Prepaid systems usually make use of a user-specific identification card including an account that can be loaded with a monetary amount. The fees for the connections of the user are then charged to this account after each connection. Various methods are known by which money can later be loaded again into the account. The parameters needed to determine the fees to be charged are known by the term CAI (Charge Advice Information), and are established at a billing center administrated by the network operator, and transmitted to the identification card of the user with signalling messages. Processing means in the card then indicate the amount to be charged on the display of the mobile device in the local currency, and debit this amount from the stored monetary amount.
Prepaid billing methods are usually cheaper for the network operator since no invoice has to be written. The amounts to be charged still have to be determined, however. Moreover this method can be applied in the GSM sphere only with devices and in geographic locations where the Advice of Charge (AOC) function, defined in standard ETSI ETS300 510 (corresponding to the technical specification GSM 02.24), can be applied. Therefore prepaid cards usually allow only very limited roaming possibilities, and often can only be used in a single mobile network.
Prepaid methods are also known in connection with intelligent network solutions. However, these methods require an intelligent network infrastructure (INI), are expensive to use, and likewise can only be applied in the network of the respective operator.
It is therefore the object of the invention to propose an improved billing method, which does not have the drawbacks of the known methods, in particular a billing method simplified for the network operator.
These objects are attained, according to the invention, with the aid of an identification card as defined in the independent identification card claim and with a method as defined in the independent method claims, various variants being described in the dependent claims.
The billing method according to the invention is carried out with an identification card for users of a terminal, which card can be inserted in a removable way in a terminal; in addition to conventional data processing means enabling the storing of data including at least identification data, (IMSI (International Mobile Subscriber Identity), MSISDN (Mobile Station Identity Number) or IDUI (International Debit User Identification), of the user, said card contains an integrated time-measuring device, with which the duration of the connection can be established, and rating means (1014), with which the fee to be billed is determined on the basis of the duration of the connection and the time of the connection measured with the integrated time-measuring device (100). The integrated time-measuring device is synchronized with an external clock signal, e.g. from the terminal.
If the identification card is used in different mobile devices, which use different quartz elements with differing frequencies, e.g. frequencies between 3.5 and 5.5 MHz, this frequency is preferably established with the integrated oscillator of the time-measuring device, and the division factor in the frequency divider is adjusted accordingly. In addition to this information, the type of mobile device, e.g. the mobile device trademark, will preferably also be recognized and stored in the memory area of the identification card for further purposes.
In this way all the parameters necessary for determining the fee to be charged can be established directly in the card so that all fee calculations can be carried out at the source, at the user.
The determined amount can then either be debited directly from a prepaid account on the identification card and/or, in the case of a post-paid card, packed in a billing record and transmitted in the telecommunications network to a billing collector.
The patent document EP 0 656 733 describes a billing system for mobile devices in which all connection parameters needed to determine the fee to be charged are stored in the memory of the mobile device. This amount can then be is shown, for information, on the display of the mobile device. Not described in this document, however, is how the determined fee can be automatically billed. Moreover the time and duration of the connection are determined with the aid of the internal clock of the mobile device. The network operator has no influence upon the accuracy of the clock in mobile devices offered by other producers. In most mobile devices this clock can be set by the users, so there can easily be abuse in that the clock is set to a cheaper tariff period.
The patent document FR 2680261 describes a telephone chipcard which contains a prepaid account as well as tariff tables. The fees billed for connections are determined from a prepaid account on the basis of call length and stored tariffs. The time and the duration of calls are also established in an external device.
According to the invention, on the other hand, the entire time-measuring device, except for the quartz, is integrated into the chipcard provided by the network operator, so that it cannot be adjusted or influenced by the user or by the mobile device producer. Moreover various mechanisms allow the accuracy and the operation of the time-measuring device to be checked by a time server in the network.
A SIM card with a continuous measuring device is already known from WO96/11545. This card can only be used for an amount of time loaded in a timer in the card. This document does not describe, however, how the amounts to be billed can be automatically charged to the customer.
EP 0 770 953 describes another chipcard with an integrated clock, which can be used, however, only for signing electronic documents, and not for billing of connections.
A SIM card with an integrated timer (xe2x80x9cclockxe2x80x9d) which can be used to determine the duration of connections is described as a variant in the patent application WO97/40616. This document does not describe, however, how the clock can be synchronized. How a quartz crystal can be incorporated into a chipcard was not known at the time of this application, however. A non-synchronized, electronic clock has a precision of approximately one percent or about one quarter hour per day; moreover the possibility is not mentioned that the time on the clock can be checked and controlled remotely. The SIM card described therefore can hardly be used for any precise billing of fees.
Furthermore the SIM card described in WO97/40616 contains no prepaid monetary amount, so a second prepaid card with an electronically stored monetary amount is needed. The two cards have to be inserted into the mobile device at the same time, or one after the other. An extensive modification of the mobile device is thus necessary so that the two different chipcards can be received. Consequently this system can hardly be used for modern, miniaturized mobile devices.
In contrast, in the identification card according to the invention the clock can run very precisely because it is synchronized with an external clock signal, for example from a quartz crystal in the mobile device. In addition, the set time can be checked at any moment by a central station, and, if necessary, adjusted. At most only minimal adaptations will be necessary on mobile devices in order to use the method according to the invention.
Described in the patent application FR 2 613 101 A1 is a chipcard, in particular a card for payment purposes, which can be connected to an external device, for example a card reader. The chipcard described in the patent application FR 2 613 101 A1 further comprises an interface circuit with a frequency divider by means of which the timing rate of a clock signal supplied by the external device can be divided down so that a suitable timing rate for the data transfer between the card and the external device can be derived in the card from the timing signal supplied by the external device.